Chinese E-stop button teardown. All FORTY bits of it!

Thanks to China's heavy industry, eBay is awash with just about every industrial control component you could desire. OK, not always the best quality, but fine for personal projects.
This is an E-stop button (Emergency stop) that has a large mushroom head to whack in the event of emergency and then latches in. They are normally wired in series with the control circuit to kill power to most of a machines components.
I bought this one just to see what sort of quality it was. And visually it looks absolutely fine. It does have proper contacts of unknown composition and seems quite robust. More robust that some big-brand ones I got for a gas jet shut-off system some time ago that literally fell to bits after a few uses. I can't remember the brand, but it was high enough profile to be surprising when they failed.
This switch is surprising for a different reason. It has no less than FORTY separate bits. It's actually worth buying purely to use as an engineers jigsaw puzzle.
It comes with a normally closed (control circuit) switch and a normally open (E-stop signal) switch, and the switch modules are the type that can be paired and stacked to the required number of circuits. They're probably compatible with a whole range of buttons and actuators. (They are... search for LAY37)
The locking and releasing system works fine. It passed my "beat the crap out of it" test with flying colours.
Here's a link to the ebay listing I bought it from. http://www.ebay.co.uk/itm/201403616296